walp DIY 3.49m wind power generator project

[walp]

Hello!

I would like to share my DIY wind mill project with you guys:
It's an induction motor conversion generator with caps, together with a home built digital load controller and some tree blades.


1. http://www.youtube.com/watch?v=nY3FYf1QXTg - From idea to reality

2. http://www.youtube.com/watch?v=wl1mMGOJuMM - Digital Load Controller

3. http://www.youtube.com/watch?v=EE3hEzLTNp0 - New 3.49m blades

4. http://www.youtube.com/watch?v=_qIbGZxO89U - Tower building

5. http://www.youtube.com/watch?v=EFMULCVNbqE - Final result

Hope you enjoy the videos!

\walp

[Warrior]

Congratulations!! Very nice project! Kepp us posted with your larger version 

Warrior

[DanielInSweden]

Congratulations!! ..and thank's for sharing your pictures, it gives me a lot of energy..   I'd love to see more pictures and know how about the generator build, gearing, controls etc.. I'm leaning towards building DanB's 20' turbine but if I can get a good concept based on a standard asynchronus motor that might change my mind..

[walp]

Thank you both for the cred!
Always nice to get some good ol' Pavlov acknowledgement!

For those who understand swedish there's a lot of info and pictures in the swedish electronics forum:
http://www.elfa-elektronikforum.se/cgi-bin/YaBB.pl?num=1270389661

I will give more info about the build and relevant pictures in this forum next year..

What is DanB's 20 footer? Its sounds interesting! Any link or thread maybe?

Now Im gonna hit the sauna

[DanielInSweden]

Great, thank's!

Link to DanB's 20 footer  http://www.otherpower.com/20page1.html

I'm a Swede too Located near Trollhättan, where are you from?

You can follow my project at http://24volt.eu/phpBB3/viewtopic.php?f=16&t=1806

[dnix71]

If you watch to the end of the last video it answers questions I would have asked. This is just a trial run. The next mill will be designed with batteries and inverters and will run the farmhouse.


Great work guys.

[walp]

Ahh, I had a clue that it was that 20' turbine which I have studied before.. really nice! Except that it is a tedious pancake
We´re both from the northern part of Sweden,(Umeå)

DUDE! Thats a very nice tower! I might buy a ultra stable 8m rail road electricity lattice tower for 450$ to the new project, the 8m will due, since the winds are very strong at low level near the sea where we live


If you have any more questions about the videos, "don't ever hesitate!" as John Mason(Sean Connery) in 'The Rock' put it..

[walp]

Okey, here's the deal when it comes to the new turbine plans.


What we got:
-A (cheap : ) 7.5kW 1400rpm 3-phase induction motor that is just laying around         0$

-A digital load controller (currently used to the 3.49m turbine)    0$

-An analog load controller... (currently un-used)       0$
(which can be seen in this movie http://www.youtube.com/watch?v=u71tD8EFmxE ).


What we need:
-A lot of capacitors (60-80µF/kW, which will be 15-20 capacitors rated 30 µF)  ~150-250$

-Some kind of transmission (Rougly 10:1), and we are at the moment pretty keen on belt transmissions since they are cheap, reliable and easy to construct. We have a idea of a concept that is cheap and simple to manufacture...  100$ ?

-A 50-100m 3G5mm² cable , (32A @ 230V, which is rather overkill).. 150-300$

-A tower, and as said before, we are interested in a robust 8m rail road electricity lattice tower

-Some kind of base for the tower, will probably be a mix of large stones and reinforced concrete. Around 300-400$ for the tower and an unknown amount for the base (how large a base is needed for a free standing tower by the way?)

-5-7m diametre blades (currently undecided)  50-100$


..more to come

[walp]

I just realized that you can't edit old posts, which is too bad for me who needs to correct a lot of grammar apparently... ^^

Awell, when using the simple blade calculator ( http://windpower.org.za/bladecalcs/blades.php ) and submitting the values ranging from 2500m radii, to 3500m radii, the RPM, and approximative wattage needs to be evaluated for two windspeeds, the mean wind speed (5m\s) and the maximum windspeed for the generator before it starts to furl (10-13 m\s) ?

The RPM analysis is straightforward. The generator specified 1400 rpm divided by the turbine rpm at 5 m\s equals the gear ratio needed for the turbine to give ~200V @ mean wind speed, which is nice.
Furthermore, the RPM at higher wind speeds should not be greater than, say twice the rated motor speed (?) (Anyone who knows the maximum asynchronous motor speed for 4-pole generic motor?)

The wattage however, is more complicated, I am used to calculate the total efficiency by multiplying the generator efficiency 0.8, with the approximate blade efficiency 0.33, and at last, a constant 0.9 for losses in belt transmission, i.e  0.8*0.33*0.9 = 02376 which is equal to Betz'/2.5    ( 0.593*0.4 = 0.2376).
This can be compared with the old 3.49m turbine, which have a generator efficiency of only 0.7, but an ideal 3-bladed rotor (~0.33) and sadly, a very bad gear assembly, which may be as low as 0.8

Thus, 0.7*0.33*0.8 = 0.1848, which is approximately one third of the Betz' limit, which is a fairly good approximation when compared to real wattage vs. calculated wattage at specific windspeeds. (However the swiftly changing gusts might induce some errors..)


Is there anyone who can supply me with some real life experience turbine wattage vs calculated wattage to estimate the total efficiency? I understand that most people use PMG's, but it doesnt matter!


Now, the limitations of the build are:

-Cable specific (32A*230V = 7360 W)
-Digital load controller 4 x 250V * 10 A = 10000W max, but since it is nice to have incrementally increasing steps, the theoretical max is more like 625 + 1250 + 2500 + 2500 = 6875 W
-Transmission cant be too large, else it wont start, and it gets mechanically problematic to build also.
-Tree (the not glued together ones) blades cant be too large, else they will easily break.


...more to come!

[niall2]

my god walp.....thats a lot of theory  ...

i really liked the video you did with the the stones "start me up" over dub ...are you the one getting the slow  mo punch in the face ?

anyway , very nice work and looks like a lot of fun (i like the Alaskan chainsaw jig ) 

[walp]

No, that's Tom, a comically laid friend of mine, being hit by his sister. It's captured by my Casio Exlim F1 300\600\1200 fps camera (rather low resolution though.. :/)
I happend to like theory...as a matter of fact, I'm getting my masters degree in radiation physics this summer (Currently writing my masters thesis on a new kind of radiation therapy).

Ontopic:

Since no one seem to have any information regarding turbine efficiency, I made a simple estimation from 46 turbines enlisted in Hugh Piggotts 'Choosing Windpower'.

The result can be seen below, and the mean "dividing factor" of the calculated power from Simple Blade Calculator (http://windpower.org.za/bladecalcs/blades.php) is 2,6, and as I predicted for the new build , it will be 1/0,8*0,9*0,33 = 2,5, which is very close to the calculated mean, and may therefore be a nice 'guesstimate'. However, there are large fluctuations between the 46 turbines, mostly due to the large spectra of blade diameters used, but also the fact that the data is based on manufacture specifications, which implies that some may be tested in a laboratory wind tunnel...




Please comment if you have an objection , questions or have some more information to share regarding the above table!

[DanielInSweden]

I was lucky enough to get the tower for ~$500 a moto cross club nearby. They had planned it for speaker tower but never completed it..good for me

I'm following your plans with great interest and I'm more and more tempted to try something similar to what you do. I'm not as skilled though as you are on the theory but willing to learn..

..some sites with standard motor conversions
http://www.prairieturbines.com/
http://www.flowtrack.com.au/
http://www.byggvindkraft.se/

[ghurd]

I do not have the book.

Efficiency decreases with current.  You knew that.
Advertising is often misleading or a lie.  You knew that.
Test results depend on the measuring equipment.  You knew that.

You did Not know I beat Betz (according to the measured data) with this super scientifically designed wonder turbine,
http://www.otherpower.com/images/scimages/2050/ugly30efkabuckt.jpg

I do not believe many people have the ability to accurately measure and record all the factors.
Small things like the top of the tower being slightly off level, a % or 2 error in this measurement and that measurement, windspeed, wire run distance, rectifier characteristics, induction and reactance, lag in blade speed vs anemometer RPM, turbulence if the wind comes from the NW instead of SW, etc,
will all have a substantial impact on the accuracy of the calculations.
Meaning: I doubt many people have data they are comfortable with proving the accuracy of their test results and calculations.

Very nice project.

I can not find å on my keyboard!
G-

[walp]

I was lucky enough to get the tower for ~$500 a moto cross club nearby. They had planned it for speaker tower but never completed it..good for me

I'm following your plans with great interest and I'm more and more tempted to try something similar to what you do. I'm not as skilled though as you are on the theory but willing to learn..

..some sites with standard motor conversions
http://www.prairieturbines.com/
http://www.flowtrack.com.au/
http://www.byggvindkraft.se/

 
$500 ?  That is such a steal... poor moto\enduro club..
I would probably trade my annoying sister for such a tower.

The sites you linked to were interesting, but most of them were grid connected, so that is out of our leauge :/
However, one of the controllers are very similar in function compared to our home built one

...Back to our ongoing project!
I was in my cottage the other day and searched for usable items when it comes to transmission\gears, and I found a 40cm diametre thin ribbed 3cm thick disk (currently used as a gear for an old grinding stone), that might come in handy, else we will try to use a couple of bicycle rims (28", not actually inches, but close to) to supply the 8-10x gear ratio, however, this might prove totally FUBAR since they are subject to a lot of slipping.., awell, time will tell.


To Ghurd: People might or might not have fancy measurement equipment, but nevertheless have to use a wee bit of common sense. And as a future physicist, I will try to learn people to think about what they are measuring, how it is connected to other input data, and estimate\calculate how large the error might be.
As an example, I just read a thread on a swedish green-energy-forum about a 6,4m turbine which delivered 2,4kW according to the included LCD-display, in a 4 m\s wind, and the owner (and manufacturer) actually believed on the LCD-display, rather than on the 10 people spamming him in the forums with different theory graphs and calculation examples. The facepalms where everywhere! Iiih!


Pretty nice output on a 6.4m diametre turbine indeed!


Ghurd, I would like to see the measurement setup of "your" fancy wind turbine



Offtopic:
I´ve just recieved two 1\2 hp 170V, 2,4A 1500rpm electric DC-motors and wanted to build a very small simple turbine of that, is it possible to connect the output to a computer PSU to get stable 12V as long as the generator voltage is high enough to trigger the PSU (i.e in the 80-250 V range) ?
Then I would connect it´s 12V-leads to a solar cell charge controller for car battery chargeing purposes... or something like that..

Is it plausible?      


Edit: Ah, so it is possible to edit, but only the latest post..    That's so sad, since one of the links in the first post is wrong, is there now way to change it without contacting admins?

[ghurd]

Ghurd, I would like to see the measurement setup of "your" fancy wind turbine

My measurement and data recording system is very complex.   

The controller records data for one measurement at a time, the controller inputs the data into a combining device, and that data is recorded in the same memory as the original measurements, for long term storage in a first-in/last-out format.

Because English is not your first language-
The controller (me) records data for one measurement at a time (amps, volts, wind speed), the controller (me) inputs the data into a combining device (calculator), and that data is recorded in the same memory as the original measurements (the paper), for long term storage in a first-in/last-out format (desk drawer).

[Fish4Fun]

walp,

First, let me say, Very nice work!  The amount of effort you have put into your project and the photo-documentation is great!  I look forward to seeing your future projects.

Since no one seem to have any information regarding turbine efficiency, I made a simple estimation from 46 turbines enlisted in Hugh Piggotts 'Choosing Windpower'.

The truth about efficiency in a small scale wind turbine is that there are many non-linear variables that are difficult to calculate/capture.  For instance, measuring the wind speed the turbine sees is always a compromise because the measuring device and the turbine cannot occupy the same space w/o affecting each other.  The rotational inertia of the blades/alternator prevent them from responding to changes in wind speed as rapidly as an anemometer.  The electrical efficiency of an alternator varies with input RPM.  Etc, Etc.  This does not mean that data logging won't give you a pretty good idea of an average efficiency over time, it simply means that many "instantaneous readings" may give somewhat misleading results.  From a theory point-of-view we tend to want things like TSR and Efficiency to be "constants", but in reality both TSR and Efficiency can vary greatly.  In the end, it is often easier in small scale turbines to use trial and error to "tweak" your build rather than rely too heavily on predictions based on calculations. 

I think the #1 thing you could do to improve your conversion efficiency would be to replace your induction motor/generator with a three phase PMA.

Again, great work!

Fish

[Janne]

Hi walp,

First of all, nice work with the turbine. It's good to see an "old fashioned" design work well.
Some thoughts about the bigger turbine.. I think, if the regulations allow, you should opt for a taller tower to get the most out of the bigger machine. Would be a shame to cripple the output with a too short tower. Depends also of course of your site, if there are not much trees around the location of the new machine, it could work to some extension with that short tower too.

The induction motor with capacitors is a cheap and tested method of making power. However, I'd still consider using a permanent magnet generator instead of the plain induction motor, for the ease of it. I've just finished putting together a controller for a similar 3kW turbine, and there was actually quite a lot of things to figure out. First of all, a secondary tachometer was required to measure the speed of the generator, as it is sometimes possible for the induction motor NOT to excitate with capacitors, especially after long periods of runnign just below excitation speeds. The controller then needs to charge up one of the capacitors from the battery bank, to give the stator a jolt of current and excitate the generator again. The problem of switching the capacitors with the change of wind speed is also another headache you have with those. So induction generator is well possible, it's just much more headache than plain permanent magnet generators.

Other than that, all problems of building a big turbine apply, overspeed control, brakes etc.. all need to be figured out to make it safe. If you have beefy enough brakes on the slow speed shaft, that alone with automatic braking in case of overspeed might be enough, but pitch control would be preferred as backup in case of any electrical or other mechanical fault.

If you can understand finnish, I can send you a link to a ~2hr video about building and flying these "traditional" windills. Along with the problems one encounters in the build and test runs.

[walp]

To Ghurd: Haha, I did actually understand the subliminal message (or what is it called..) in your post
(And even though I don't have english as my first language, I still got a CAE (certificate in advanced english), which I obtained during my high school years! Those were the days..



To Fish4fun: I won't even touch the PMG's with a nine foot pole! But the splendid poles of an induction motor.... *Jummy!*
I know this is like swearing in the church, but I consider the PMG's to be all to expensive and tedious to build!
About the estimation of power\efficiency; the P α v³ implies that a small change or error in wind speed, yields a large error in the effect and thus efficiency, which (all of you) implied..!)



To Janne: Thank you! Yeah send me the video, but tell me.. the finnish instructor don't happend to be Vesa Mikkonen? ^^ He´s such a legend..! I even have his $100 "leaflet" or (what to call it), even though I don't understand finnish at all

Furthermore Janne, did you miss that we already have a digital load controller which wont load the generator until it's magnetized.
We have actually never lost magnetization of the motor during extensive testings, with no need for reflashing it with a battery bank or so,
maybe we just have been lucky 

I don't really understand this particular line you wrote:
"The problem of switching the capacitors with the change of wind speed is also another headache you have with those. So induction generator is well possible, it's just much more headache than plain permanent magnet generators."

Does the controller switch capacitors between D\Y or something like that depending on the wind speed? Please explain, sounds interesting




Many Thanks for showing interest in my projects

[Janne]

Hi,

The failure to excitate may be motor specific, I know of a couple of ocassions when it happened after extensive times of running below excitation speeds. Those motors even had a small magnet drilled to the rotor to help it excitate. Mayby the motors could be tested, by running them in a variable speed test benches for lenghts of time, and see if they still work ok, to figure out if the particular motor will work perfectly. Though in reality, if you have a battery bank that you're charging with the machine, the automatic flashing is then quite easy to apply. (provided you have additional speed sensor spinning in the machine)

The generator on the windmill I build the controller for has always 3x50µF connected in delta, and another 20µF can be switched on / off depending of speed. At startup, the full 70µF is connected, but after the second heating load is switched, the additional capacitors are also disconnected.  In case the final 0.75kW load is switched, then also the 20µF capacitors are swithed back on, to help reduce speed. The machine has automatic blade governor, so it should prevent the need of the final 0.75kW load, if all works correctly.

Check your pm folder, I posted the video address in there.

[walp]

Thx for the links!

I´ve been really busy with the masters thesis (doseplanning for the win..!) so I have'nt been able to do so much wind power associated stuff lately.. (for example putting up the requested pictures!)

But I have at least just tested out my two 170V 2,4A 1500RPM DC-motors that I bought cheap on teh internets.

I fixated the motor, connected the leads accordingly, and measured the voltage when driving the motor with a hand powered electric drill, which made the voltage go dangerously high!
Then I connected a large (90-264V -> 19,7V (3.9A max)) lap-top power supply to the motor, and pressed the drill as hard as I could against the motor shaft while pressing the trigger,
*KABLAMWEB!*

Seconds later, blood where dripping from my thumb and the poor concrete floor got some serious bruising. I had manage to press the attached motor out of the vice (I must indeed be very strong, or maybe the other way around, unable to tighten the vice accordingly..) 

Anyhow, the motor seemed fine, except for a totally unimportant M6 bolt that was bent 90 degrees, but when I tried to rotate the axis by hand, it made a very scratching sound and cogged like hell!
I dried some blood from my thumb and thought,
"DAMN! Now I only have one motor left!" 

But after disassembling the thing into pieces (springs where flying all over the place from the commutator slip-rings ), I found that one of the eight large traditional magnets where turned into a pile of dust by the combination of a crash and my attempts to rotate the shaft by hand. So I simply just removed the broken magnet + the pieces, and vacuum cleaned the whole motor for magnetic splinters.

Putting the motor together was a wee bit harder... springs had to be meticulously replaced and the rotor was more than unvilling to be inserted into the stator.. stupid PMG's, I hate them already!

Anyhow, Glad to see that a 40W 24V lightbulb actutually ran very smooth from the power supply, even at half specified rpm (~750rpm)
I even connected the poor motor to a 12V car battery and it ran very nice and strong, though a bit slow.  (Might use it as a starting engine for the bigger turbine with a solenoid-connector?)

BAh, to much yakking! Good night!

[zvizdic]

Congratulations!! ..and thank's for sharing your pictures, it gives me a lot of energy..   I'd love to see more pictures and know how about the generator build, gearing, controls etc.. I'm leaning towards building DanB's 20' turbine but if I can get a good concept based on a standard asynchronus motor that might change my mind..

I also think as Mr. Daniel. If I could have used 10 HP 220V motor would be good because I have one lying around.

[walp]

Yeah, thats exactly what I'm talking about! Using mainly scraps to be really competative when it comes to pricing!

And as the matter of fact, I just came up with a plausible solution to the whole friggin' gear-up problem!

Since belt transmission is the best way to go as far as I know, and belts are cheap but very large belt pulleys are either too expensive and\or heavy.

I described my thoughts about using old bicyclerims as belt pulleys before, but they are either to small and\or too weak() and are subject to a lot of slipping unless you use multiple rims.

One way to go is therefore building your own 3-leaded belt pulley in the desired size by using a multi layer technique with plywood and thin metal sheets of either aluminum or steel.

Also? Is there anyone out there who like Janne have tried to use both capacitors and countersunk magnets on the rotor of a induction motor?

I know the great Zubbly also did a lot of experimenting with magnets on squirrel-cagers but I dont know if he ever combined them with capacitors?
Would be really cool if you could excite the motor at a much lower RPM, (giving just a few volts) making it possible to rectify and charge batteries or so.
Do you know more about the excitation magnets Janne?

Until we know that Its a nice method, I better start working on the massive belt pulley assembly instead..

[zvizdic]

I am a millwright so take my word for, no skimping on a pulleys and no belts it is a 10 HP your talking abut.



This is a way to go on a big machine.

Big and strong bearings maybe a chain from a car engine or two.

It is  ChrisOlsons Wind Turbine Transmission

[MattM]

Is that pivot a little close to the rotor?

[zvizdic]

Sorry Chris

[walp]

Haha Zvizdic! The only thing you are doing is getting me more and more determined to go the cheap and simple belt pulley-way 
(My much more mechanically experienced father would and could have built something chain-like that in the picture though..but he's always so busy :/ )

Yeah I know belt transmissions have some flaws, and that 10hp is a lot of power!
But hey, what is my calculated maximum power output now again?

The load controller can handle (2500 + 2500 + 2500 + 2500) watts, but for a smoother ride, 500 + 1000 + 2000 + 2500 is recommended, (i.e 6000W)
Thats about 8 hp at MAX, divide this by three belts and you have a mere 3hp per belt and since we will use correctly dimensionated pulleys, slipping wouldnt be a problem at these maxloads.

A belt tightening gizmo would be nice to round up the concept, it's not that complicated to implement.

What are your biggest concerns regarding this kind of poor-mans solution? (Maybe that long belts tend to stretch in time and that the grip on the smaller pulley may be too small due to bad geometry)

Would you rather recommend a custom built two-stage motorcycle chain-gear like the one in the picture? i.e (3.3:1)*(3.3:1) for 10x gear?


Please give me as much info as you can cause this is really the essential core of this project!

[zvizdic]

http://www.friesen.com/electric/FHPFractionalHorsepowerVBelts.pdf


Belt hp ratings

http://www.martinsprocket.com/2001/SecEc.pdf#E184

Chains

[walp]

Ah, thanks

Well, belts may work, but yeah, chains are stronger easier, but more expensive.


Other than that chained gears sound a bit more, are there any other drawbacks? More maintenance?

[wolfie]

properly sized and tensioned, and run in an oil bath, maintenace on a chain drive is a fraction of the maintenance on a belt drive

[Fused]

Chains wear out like anything else. Just hope when it breaks the blades don't over speed and go flying and hurt or kill somebody.

Just my take on keeping it simple....and safe.

Fused

[zvizdic]

properly sized and tensioned, and run in an oil bath, maintenace on a chain drive is a fraction of the maintenance on a belt drive

 Ad a safety overrating or double the rating in a charts, use motorcycle used chains and sprockets thy should bi good .

Oil bath would bi good but it is OK to grease well overrated chains.

Protect them from rain and snow whit some enclosure.

[walp]

Update: Since Sony Music removed my video "Creation of the new three tree bladed wind turbine", I have changed the music content and hopefully it will stay on the tube. 

http://www.youtube.com/watch?v=UG5Wo2CX15U&hd=1  , Enjoy!

Okey, I suppose motorcycle chains can handle quite large outputs (1-15 hp), but so can a couple of belts

Im gonna try to make the gigantic pulley later on, to see if its sturdy enough!

\walp

[Hilltopgrange]

“Since belt transmission is the best way to go as far as I know”

Personally I would disagree belts are about the worst choice I could think of for a wind turbine, they slip, stretch, rot, wear and heat due to friction and eventually break and that's when there not exposed to the elements. In the cold they become brittle and if its hot they stretch. I have seen them decay quickly when left exposed to the elements.

If used on a wind turbine and the belt breaks (which it will) you will have a runaway on your hands.

If you really must use a belt then fit double pulleys and 2 belts.

Better still use a chain preferably a duplex double chain and keep it well lubed, although I have broke a fair few of those too in the past. The last time was on a Yamaha fj1200 motorcycle at well over 100 mph thankfully I was able to stop and walk away, never rode a big bike since! that chain was top quality and only about 1 month old it even had a scott oiler fitted.

Just my opinion of belts having worked with them for close on 40 years.

Russell